Gas lift operation of wells



Nov. 26,1963 N. A. NELSON 3,111,906

GAS LIFT OPERATION OF WELLS Filed Feb. 9. 1961 4 Sheets-Sheet 1 FLOWLINE22 I I 21-- i1 VH ':-:r 5 5: H SNAP-ACTING swn'cn LL n I FIG. I.

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ANCHOR l3 Nov. 26, 1963 N. NELSON GAS LIFT OPERATION OF WELLS 4Sheets-Shet 2 Filed Feb. 9, 19 61 J :9... A Hum Hum. m 0 z 2-. M r w 2 lc m H m m o mw W G 6 H E W I A E N RPS II N un hrunu J N F L N A w M 2 ML F F, 5 R 2 O 3 5 N w w w J 5 H1 8 e m m T TW P P A A N N s s w vhhllfi n M I I mm" 8 M v D F l D D uw u E u U L E s 0 T SAL P w L S M Nw 0 O Nov; 26, 1963 r N. A. NELSON 3,111,906

GAS LIFT OPERATION OF WELLS Filed Feb. 9, 1961 4 Sheets-Sheet 3INVENTOIC NORMAN A- NELSON.

BY A

A TOR. Y.

7 Nov. 26, 1963 Filed- Feb. 9. 1961 GAS-LIFT vans; I

(OPEN) (CLOSED) (CLOSEDL N. A. NELSON GAS LIFT OPERATION OF WELLS 4Sheets-Sheet 4 FIIG.4.

24 1.0)! use 6A5 INJECTION LINE ANCHOR INVENTOR.

NORMAN A. NE LSON d -Jam United States Patent 3,111,906 GAS LIFTOPERATION OF WELLS Norman A. Nelson, Houston, Tex., assignor, by mesneassignments, to Jersey Production Research Company, Tulsa, Okla., acorporation of Delaware Filed Feb. 9, 1961, Ser. No. 88,192 11 Claims.(Cl. 103-231) The present invention is directed to the gas liftoperation of wells. More specifically the invention is concerned withoperating a system in which gas lift valves in a well tubing areoperated from the wellhead. In its more specific aspects, the inventionis concerned with method and apparatus for operating gas lift valves ina tubing string in a well wherein a signal is provided at the surfacewhich controls the operation of gas lift valves.

The present invention may be briefly described as a method foremployment in a well in which a pipe string is arranged therein whichcommunicates with a subsurface earth interval. A tubing is provided inthe pipe string which extends to the earths surface and the tubing hasarranged therein a plurality of vertically spacedapart gas lift valveswhich are operable from the earths surface. The pipe string and thetubing contain a liquid under pressure sufficient to cause the liquid toextend normally to a height suflicient to cover one of the gas liftvalves but insufilcient to cause the liquid to flow to the earthssurface. In the particular method of the present invention, a gasiforrnfluid such as a hydrocarbon gas, for example, natural gas or componentsthereof, such as methane, ethane, propane and the like, is injected intothe annulus between the tubing string and the pipe string under aselected pressure sutlicient to lift the liquid in the tubing above oneof the valves to the earths surface. Thereafter, one of the valves,which may be the same or another one of the valves, is selectivelyoperated responsive to a change in the well of the selected pressureafter a predetermined period of time, whereby the gasiform fluid isinjected into the tubing and the liquid in the tubing above said one ofthe valves is lifted to the earths surface.

The change in pressure to which the valves are responsive after theselected period of time may be a change in pressure either in theannulus or in the tubing string. When the change in pressure is in theannulus, the pressure will decrease from the selected pressure, whilewhen the change in pressure is in the tubing string, the pressure willincrease.

The selected pressure may be any pressure at which the gas in injectedinto the annulus suflicient to lift the liquid in the tubing above oneof the valves to the earths surface. For example, this pressure may be apressure such as a pressure in the range from about 500 to about 1000psi. for wells from about 3000 to about 15,000 feet in depth.

The apparatus of the present invention includes means at the earthssurface responsive to a signal which is a function of a change inpressure in the well after the lapse of a predetermined period of timefor selectively opening and closing gas lift valves in the tubingstring. This means may suitably include means for raising and loweringthe tubing wherein the valves are opened and closed or may includewireline operating means engageable and/or 'disengageable with thevalves to open and close the valves.

The present invention involves a method for automatically controllinggas lift operation by using a combination of time and pressure signalsthat result in the bottom or lower of several gas lift valves in atubing string being employed in lifting liquid :to the earths surface inan automatic operation. The removal of liquid from the tubing string mayinvolve in one mode and embodiment having all of the gas lift valvesopen initially. As gas is injected into the annulus, the well liquid isforced upwardly out of the tubing until the gas uncovers an upper of thevalves. The fluid or liquid in the tubing thus becomes aerated with gasand the tubing pressure increases with an accompanying decrease incasing pressure due to gas passing through the valve. The time requiredfor the gas to proceed from an upper valve to the next lower valvedepends upon the dimension and depth of the installation and may bereasonably determined. A controlling means reacts to the increase intubing pressure and/or to a decrease in casing pressure only after thepredetermined time period sending a signal to a means for opening andclosing the valves, such as by raising or lowering the tubing or byraising and lowering a wireline means which engages or disengagessequentially with the valves. The signal :thus causes the valves to beclosed and after the first increment if the tubing pressure does notdrop after a specified interval of time, say fifteen minutes, the valvenext lower down is closed until a drop in tubing pressure is realized.This would involve that the upper valve is closed and the fluid is nowbeing raised from above the next lower valve. After a period of time,the controller again reacts to the surface pressure and the valve nextlower down is then closed in the same fashion as the upper valve and thesequence of operation is continued or repeated until a depth is reachedbelow which the well fluid or liquids may not be raised to the surface.When the cycle reaches this point at the end of the time period, thereis no pressure in the tubing which indicates that the installation hadclosed the lower operating valve and then it will proceed upwardly tothe next upper valve which thus reopens the next upper valve and thusthe well would continue to gas lift through this valve. Thus, this typeof operation is applicable to constant flow installation.

When the well gas lifts continuously from the lower operating valve, thesurface pressures are between 2 highvlow limits. However, if a well hasa low productivity of well liquids, intermittent operations from thelowest valve may be required. This is indicated by low tubing pressuredue to closing of all the valves. When this condition is known to exist,the signm locks out the previously mentioned timers and engages a thirdtimer that opens the valve for the desired injection time and thencloses the valve for the remainder of the cycle thereby providingautomatic time cycling for intermittent operations of the well.

There are three time signals and two pressure signals controlling theoperation in accordance with the present invention. These time signalsand pressure signals are indicated in the fol-lowing table.

T1Unloading time.

TgTlllle for well to die with all valves closed.

T;-Intermitting time cycle.

P|-Pressure when well blows through.

P Pressure when well is dead.

Ps-PICSSUI'G wlen well ls constant flowing on intermediate pressurebetween P and P2.

are K The invention will be further illustrated by reference to thedrawing in which:

FIG. 1 is a view in partial section of one preferred mode andembodiment;

FIG. 2 is a partial sectional view of another mode and embodimentemploying wireline operated valves;

FIG. 3 is a partial sectional view of a mode and embodiment employinghydraulic or pneumatic energy; and

FIG. 4 is a similar view to FIG. 2 employing hydraulic or pneumaticenergy.

Referring now to the drawing in which identical numerals will beemployed to designate identical parts and particularly to FIG. 1,numeral 11 designates a well casing having a tubing 12 arranged therein.The tubing 12 is arranged and locked into place with a tubing anchor 13.Vertically spaced in the tubing 12 are a plurality of gas lift valves14, 15 and 16 having parts which are movable relative to each other suchthat in one position the gas lift valve is closed and in anotherposition the gas lift valve is open. In other words, by raising orlowering the tubing 12, the gas lift valves 14, 15 and 16 may be closedor opened.

The tubing 12 extends to the well head through a stuffing box 17 whichprovides a seal but allows the tubing 12 to be moved vertically. Thetubing 12 has arranged thereon racks 18 which engage with pinions 19powered by gears 20. The tubing 12 extends above the earths surface andis connected to a flexible section 21, which in turn connects to a flowline 22.

The casing-tubing annulus 23 is in fluid communication with a gasinjection line 24, which connects to the casing 11 below the stuffingbox 17. The gas injection line 24 connects by conduits 25 and 26 topressure responsive means P and P respectively.

Pressure responsive means P and P form part of a surface controllergenerally indicated by numeral 27 and including well-known, electricallyoperated timers T and T as well as T Solenoids 28, 29, 30, 31 and 32 areprovided in controller 27 for controlling respectively T P P T and T Thesolenoid '32 is connected to a switch 33 by means 34, while the solenoid31 is connected to a switch 35 by means 36. The solenoid 30 is connectedto switches 37, 44 and 45 by means 38, and the sole noid 29 is connectedto switches 39, and 46 by means 41. The solenoid 28 is connected toswitches 42 and 47 by means 43. The electrical circuitry involves anelec trical connection 72 between T and switch 39 and electricalconnection 73 between T and switch 45 while T connects into switch 46which in turn connects with switch 44 by electrical connection 74. Talso connects into a switch 47 which connects by an electrical lead 48into a snap acting switch 49, and connects to lead 53. The switches 50and 51 on P and P respectively, and timers T T and T connect by suitableelectric leads 52a to an electric power source 52 and control solenoids30 and 29, respectively, through electrical leads 70 and 71,respectively and solenoid 28 through electrical lead 69.

The leads 48 and 53 connect the surface controller to the controls ofmotor 66. The switches 49 and 54, which are similar, are operated bysolenoids 55 and 56, respectively, and the switches 49 and 54 areoperated by switch openers 57 and 58, which are pivotally arranged onpivots 59 and 60. The switch openers 57 and 58 are operated by a springurged means 61 which is provided with a cam follower 62 engageable witha cam 63 operated by a gear 64 engageable with a gear 65 connected to amotor 66. The motor 66 is operated through leads 67 and 68 which connectrespectively to switches 49 and 54. The gear 65 connects to one of thegears 20.

The timers T T and T connect to solenoids 32, 31 and 28 by electricalleads 67, 68, and 69 while the pressure responsive means P and Pelectrically connect to solenoids 30 and 29 by electrical leads 70 and71. As mentioned, the timer T is electrically connected to switch 39,and this is done by an electrical lead 72, while the timer T connects toswitch 45 by electrical lead 73. The timer T connects into switch 46 byelectrical lead 74, and, as has been indicated, T connects by electriclead 53 to switch 54.

The pressure responsive means P and P may be connected by conduits 25and 26 to flow line 22, and it is understood that these pressureresponsive means P and P may form part of a surface controller 27 as hasbeen described, the only dilference being that the conduits 25 and 26will be connected to the flow line 22 rather than to the gas injectionline 24. When conduits 25 and 26 are connected into the gas injectionline 24, a decrease in pressure in the annulus 23 will cause theoperation of the device after the lapse of time indicated, whereas ifthe conduits 25 and 26 are connected to the flow line 22 an increase inpressure in the tubing 12 after a lapse of time will cause operation ofthe valves 14, 15 and 16, as will be described further.

Referring now to FIG. 2, where identical numerals will be employed todesignate identical parts, the tubing 12 is provided with a stufiing boxwhich closes the upper end of the tubing and allows the use of awireline 81 which is in the well and is connected to a sinker bar 810.The wireline 81 is spooled onto a drum 82 which is connected by a gear83 to a gear 84 on a suitable electric motor 85. The gear 84 in turnconnects with the gear 86 which is connected to a cam 87 which engageswith the cam follower 62.

Arranged in the tubing 12 are a plurality of valves 88, 89, 90, and 91which are spring biased such that the valves 88 to 91 are normally in aclosed position. As the sinker bar is lowered into a valve such as 90,the valve mechanism depresses a spring such as 92 and allows opening ofthe valve communicating with the annulus 23 to allow passage of gas intothe tubing 12.

The other elements of the embodiment of FIG. 2 are identical to anddesignated by identical numerals to the parts in FIG. 1. Therefore,further description thereof is not required.

Referring now to FIG. 3 wherein identical parts are designated byidentical numerals, in this mode and embodiment the mechanism isoperated by a liquid from a hydraulic pump or by gas or pneumaticpressure. In this particular instance, the pressure responsive means Pand P and the timers T T and T may be similar to those in FIG. 1 andFIG. 2, but here the timing devices such as T T and T and the pressureresponsive means P and P connect by suitable conduits to valves whichare either pneumatic or hydraulic and which are operated responsive tothe pressure and time signals from the timing devices and pressureresponsive means. The timers T T and T in the embodiment of FIG. 3 maybe wellknown fluid operated timers receiving fluid energy from anexternal source (not shown) or may contain as an integral part thereofwell-known energy supply means such as clockwork mechanisms In thisparticular instance, a supply of hydraulic fluid 01' gas under pressureis admitted by line 100 from a source, not shown, to a valve 101 whichis connected by means 102 to timer T The valve 103 is operated by means104 connected to timer T The timer T also connects by conduit 105 to avalve 106. The timer T connects by conduit 107 to valve 108 and valve108 is interconnected by conduit 109 to a pressure responsive means 110.The pressure responsive means P is connected through an arm and linkage111 to valves 106, 115 and 122, while the pressure responsive means Pconnects by arm and linkage 112 to valves 113, 124 and 126. Valve 101interconnects by a conduit 101a to valve 103 and interconnects byconduit 114 to valve 115 and by branch conduit 128 to valve 106. Valve115 connects in turn by conduit 116 to a conduit 117 which, in turn,connects to a valve 118 interconnected with conduit 109 and pressureresponsive means 119 which, in turn, connects into valve 113 which isinterconnected by conduit 120 with valve 115. Valve 103 is connected byconduit 121 with valve 122 which, in turn, connects by conduit 123 withvalve 124 which connects into conduit 117 and thereby communicates withvalve 118. Valve 122 connects by conduit 125 with valve 126 whichinterconnects by conduit 127 with T Valve 106 connects by conduit 105with T The several timing devices T T and T and pressure responsivemeans P and P make up a separate controller enclosed by the dotted linesand indicated generally by the numeral 130. Conduits 131 and 132 leadfrom the surface controller 130 into snap acting valves 133 and 134 andconnect, respectively, to valve openers !135 and 136 by suitable conduitand interconnection means as shown. Valve closers 57 and 58 servefunctions similar to those of switch openers 57 and 58 of FIG. 1. Theother mechanisms employed in FIG. 3 are identical with the mechanismsemployed and described with respect to FIG. 1 and, accordingly, aredesignated by identical parts. However, the motor 66 in FIG. 1 isreplaced by hydraulically or pneumatically operated motor 137 to whichthe gear 65 is attached which meshes with the gear 64 to which the cam63 is operatively connected.

As has been described with respect to the other embodiment, the surfacecontroller 130 may be connected into the flow line 22 rather than intothe gas line 24 as shown. As indicated in the dotted lines, P and P mayconnect by conduits 25 and 26 into the flow line 22.

Referring now to FIG. 4, identical parts are designated by identicalnumerals to those used in FIG. 2 and FIG. 3. In other words, the surfacecontroller 130 of FIGS. 3 and 4 are identical and are designated byidentical parts, and the hoisting mechanism of FIG. 2 and the attendantoperations are similar to those of FIG. 2, while the valves 133 and 134and openers 135 and 136 and closers 57 and 58 are identical to those ofFIG. 3. Therefore, in the interest of briefness, further description ofFIG. 4 is not required.

The present invention will be further described with reference toFIG. 1. In this particular operation, all of the valves 14, .15, and 16will be in the open position. Well liquids will be present in thecasing-tubing annulus 23, to some level above valve 14, and gas will beforced under pressure through the gas injection line 24 into the annulus23, causing part of the well liquids to move through the valves 14, 15,and 16 into the tubing 12 and thence to flow line 22. Gas will continueto be forced into the gas injection line 24 in sufficient amounts and 6under suflicient pressure to create and maintain a flow of the wellliquids into and through the flow line 22. As lifting continues, liquidswill be removed from the well above valve 14 and the gas will blowaround, causing pressure in line 24 to be reduced. The timing device Tis on and at the end of a predetermined period of time, say 45 minutes,and simultaneously with the end of this time, solenoid 32 is energizedand shifts switch 33 to allow an electrical impulse to flow to switches44 and 45. The pressure in line 24 is assumed to be low, causingpressure-responsive device P to close switch 50. This energizes solenoid30, causing switches 37 and 44 to be shifted and switch 45 to be closed.The electrical impulse flows through switches 45 and 44, andsimultaneously through lead 73 to timing device T and through switch 42and lead 48 to switch 49. The impulse to T 2 causes T to start. Theimpulse to switch 49 causes motor 66 to be rotated one revolution and inan amount suflicient to raise tubing 12 and thereby close valve 14.Timing device T holds solenoid 32 on for a period of time, say 5minutes, suflicient for valve 14 to close and timer T to start, thenshuts itself and solenoid 32 off allowing switch 33 to return to normal.After timer T has run for a predetermined period of time, say 15minutes, it causes solenoid 31 to be energized, causing switch 35 toclose. The pressure in line 24 is assumed still to 'be low, and thuspressure-responsive device P still causes switches 37 and 44 to beshifted and switch 45 to be on. When switch 35 is closed, an electricalimpulse is allowed to flow through switch 35 to switch 37 to switch 40to switch 42 through lead 48 to switch 49, causing motor 66 to beactuated and raise the tubing 12 and thus close valve 15. Timer T causesswitch 35 to remain closed for a period of about 5 minutes and then openagain. After a second period of say 15 minutes, timer T again causesswitch 35 to close. Assuming the pressure in line 24 is still low, asequence similar to the one just described will cause valve 16 to beclosed.

If, however, the pressure in line 24 is at an intermediate stage at theend of the second 15-minute period of T pressure-responsive device Pwould cause switch 50 to open, causing switches 37 and 44 to return tonormal position and switch 45 to return to off position. Also,pressure-responsive device P would not have caused switches '39, 40, and46 to operate and so no action would take place relative to positioningthe several valves .14, 15, and 16.

If, on the other hand, the pressure in gas injection line 24- has becomehigh at the end of any 15-minute period of T then pressure-responsivedevice P would have closed switch 51, causing solenoid 29 to beenergized and causing switches 39 and 46 to be closed and switch 40 tobe open. Thus, when timer T causes switch 35 to be closed, theelectrical impulse could pass through switch 35 to 37 to 39 through lead72 and cause timer T to start again. Simultaneously with the starting oftimer T timer T will receive an electrical impulse through lead 74,causing it to stop.

At the end of the predetermined period for timer T say 45 minutes,solenoid 32 will be energized, and assuming pressure in gas injectioniine 24 is still high and switch 46 is thus still closed, an electricalimpulse will pass through switch 33, through 44, through 46, and onthrough leads 74 and 69 to timer T and solenoid 28. Solenoid 28 willturn switch 42 off and switch 47 on. These switches will remain in thesepositions until manually reset. The impulse to timer T starts T which atthis time takes control of motor 66 and causes intermittent opening andclosing of whichever of valves 14, 15, and 16 was last closed.Energizing solenoid 28 results in any further signals due to timers T orT being blocked from reaching motor 66, as switch 42 is in the openposition. After a brief period of time, say 5 minutes, timer T shutsitself and solenoid 32 off.

With respect to FIG. 2 wherein the surface controller 27 is identical tosurface controller 27 of FIG. 1, the operation is identical to thatdescribed with respect to FIG. 1 excepting that a hoist motor and a drumcarrying a wireline 81 is used instead of raising and lowering thetubing 12 to close and open the valves. In short, with respect to FIG.2, the same particular operations are employed to open the valves 88,89, 90 and 91 by raising and lowering the sinker bar 82 on the wireline81 by rotation of the hoist motor 85 and thus rotating the drum 82carrying the wireline 81. It is believed unnecessary to burden thisdescription with further descriptive matter of the surface controller 27in view of the detail that has been given with respect to FIG. 1.

Referring now to FIG. 3, with all of the valves 14, 15 and 116 in openposition, well liquids will be present in annulus 23 to some level abovevalve 14 and gas will be forced under pressure through line 24 intoannulus 23, causing part of the well liquids to move through valves 14,15, and 16 into tubing 12 and thence to flow line 22. Gas will continueto be forced into line 24 by means not shown in sufiicient amount andunder suflicient pressure to create and maintain a flow of the wellliquids into and through flow line 22. As lifting continues, liquid willbe removed from the well above valve 14 and gas blows around, causingpressure in line 24 to be reduced. At the end of a selected period oftime, say 45 minutes, timer device T is in operation and a force isapplied through means 102 to valve 101 to shift the valve 101 from itsnormal position and allow fluid pressure from supply 100 to proceed intoline 1 14 and line 128. If the pressure in gas injection line 24 is low,then pressure responsive means P causes the arm and linkage 111 to berotated a sufficient amount to open valve 106 and to shift valves 115and 122. This movement of the valves 115 and 122 allows pressure in line128 to pass through valve 106 and line 105 and start a period of time ofsay 15 minutes for the timing device T and simultaneously to allowpressure in line 1 14 to pass through valve 115 to line 116 and throughnormally open valve 118 and thence through line 132 to valve opener 136.This opens valve 134 and allows pressure fluid to proceed to motor 137operating it and causing valve 14 to be closed by lifting of the tubing12. After a selected period of time, for example minutes, timing deviceT causes valve 101 to be shifted back to its normal position as shown inFIG. 3. Pressure flow is then to line 101a and to valve 103 which isopened by timing device T running for 15 minutes. This allows pressureto pass into line 121. If pressure in line 24 through which gas is beingsupplied to annulus 23 is low and remaining low, the valves operated bypressure responsive means P will be in the same position describedpreviously, and pressure from line 121 passes through valve 122 to line123 and through valve 124 and thence to line 117, valve 118, line 132actuating the valve opener 136 and valve 134 and providing power fluidto motor 137 which closes valve 15 by raising tubing 12 anotherincrement. Valve 103 is once again closed after a period of say 5minutes.

At the end of a second 15-minute period, timing device T opens valve 103and allows pressure to pass to line 121. If the same pressure exists inline 24, the same sequence is repeated and valve 16 would then beclosed.

If, however, an intermediate pressure between P, and P exists in gasinjection line 24 at the end of the second l5sminute period, no actionwould take place relative to positioning of the several valves 14, 15and 16.

If, on the other hand, the pressure in line 24 is high, then pressureresponsive means P will actuate arm and linkage 111 causing valves 106,115, and 122 to return to normal positions, and pressure responsivemeans P will extend actuating arm and linkage 112 and cause valves 113and 126 to be opened, valve 124 being closed. Pressure then flowsthrough line 121 and through valve 122 into line 125, thence thepressure flow is through valve 126 to line 127 to timing device T,causing it to be actuated at the end of a 45-minute period,simultaneously pressure flowing through line 127 stops timer T At theend of this 45-minute period the timing device T then shifts valve 101allowing pressure to pass into lines 1 14 through valve into line 120.If the pressure is still high in line 24, P actuates arm and linkage 112and causes valves 113 and 126 to remain opened and valve 124 remainsclosed. Pressure from line passes through valve .113 into line 109simultaneously closing valve 118 and opening valve 108 and thus settinginto operation timing device T Timing device T now controls the motor toraise and lower the tubing 12 to open and close one of the valves 14, 15or 16, depending upon which valve is being employed. Valve 118 locks outsignals from timing devices T and T and valve 108 allows timing device Tto control the operation.

It will thus be seen that in conjunction with the operation described inFIG. 3, a hydraulic or pneumatic fluid may be used to control thecontroller 130.

The operation of the motor 137, the cam 63, the valve openers 59 and 60have been described in the previous embodiment, and in the interest ofbriefness, further reference thereto will not be had.

The operation with respect to FIG. 4 is similar to that described withrespect to FIG. 3 relative to the surface controller 130 and withreference to FIG. 2 relative to the operation of the valves 88, 89, 90and 91, as well as the motor 85, the hoisting drum 82 and the attendantequipment.

The valves shown in FIGS. 3 and 4 have adjacent thereto in the drawingthe symbols NC and NO. NC means normally closed and NO means normallyopen.

In the several figures of the drawing, the pressure responsive means Pand P as well as the timing devices T T and T are shown schematically.The pressure responsive means may be any pressure responsive means suchas a Bourdon tube as illustrated, or a bellows type device or any devicewhich will convert a pressure pulse to a mechanical force, such as apiston biased by a spring, and the like.

Likewise, the valve openers and 136 and the switch closers 55 and 56, aswell as the valves 54 and 49 are items well known to the art. Apparatuselements of this nature are manufactured by Instruments, Inc. of Tulsa,Oklahoma and by Micro Switch, a Division of Minneapolis-HoneywellRegulator Company of Freeport, Illi nois. Generally, limit or microswitches may be used in electrically powered embodiments of thisinvention, while well-known micro valves may be used otherwise.

The present invention is quite important and useful in that in theartificial lift of oil wells by gas lift, injection of gas is into thetubing from the tubing-casing annulus. This may be accomplished in wellswhere there is large clearance by installing the type of gas lift valveswhich are controlled at the valves by pressure. However, with the recentincrease in tubingless completions with a resulting reduction in welltubing and casing dimensions, a problem has been created in thatinsufficient clearance is provided in the casing-tubing annulus foremployment of the conventional type of valve which may require anincrease in the tubing size to accommodate the valve. In accordance withthe present invention, valves such as described herein are employed inan automatic sequence of operations such as that these valves may beused in areas and locations where ordinarily they are not useable.Therefore, the present invention is quite important and useful in thatit provides apparatus and a mode for operating the apparatus andarrangement by way of which automatic operation of gas lift may beprovided. Heretofore it was not practical in areas of confinement suchas experienced in tubingless completions or in slim holes to achieve thedesired objects of the present invention.

Vhile the invention has been described and illustrated by injection ofgas into the casing-tubing annulus and lifting liquid in the tubing, itis within the spirit and scope of this invention to inject gas into thetubing and lift liquid in the annulus to the earths surface.

Also, other mechanisms may be used for lif and lowering the tubingstrings or for opening and closing the valves through wirelines, such ashydraulically or pneumatically operated means embodying pistons andcylinders, and the like, or equivalent mechanisms.

In the description taken with the drawing and in the several examples,times and time cycles are given for illustration purposes only. Actuallythe times and/r cycles may vary widely depending on the particularinstallations. Thus, the times before a given signal is transmitted tooperate a valve may vary from about minutes up to about 60 minutes,although this invention is not limited thereto. Likewise, the timecycles may be multiples of the time before a given valve is operated,depending on the number of signals transmitted to the several valves ordepending on the number of valves employed.

Likewise, any number of gas lift valves may be used besides the specificnumber shown in the drawing.

The nature and objects of the present invention having been completelydescribed and illustrated, what I wish to claim as new and useful andsecure by Le'ters Patent is:

1. In a well having a pipe string therein communicating fluidly with asubsurface earth interval in which a tubing is arranged extending to theearths surface providing an annulus with the inner wall of the pipestring,

said tubing having arranged therein a plurality of verticallyspaced-apart mechanically operated gas lift valves operable from theearths surface, wherein means are provided for injecting a gasiformfluid into the Well, apparatus for continuous and intermittant operationof said well which comprises:

means at the earths surface operatively connected to said gas liftvalves and responsive to a signal which is a function of a change inpressure in said well after lapse of a predetermined period of time forselectively remotely opening and closing said valves,

means operatively connected to said opening and closing means forproviding said signal,

said means for providing said signal comprising:

first and second pressure-responsive means fluidly communicating withsaid injection means,

first, second, and third timing means,

first control means operatively connected to said first timing means forcontrolling energy supplied to said signal producing means,

second control means operatively connected to said second timing means,

third control means operatively connected to said firstpressure-responsive means, to said first and second control means, andto said second timing means for controlling energy thereto,

fourth control means operatively connected to said secondpressure-responsive means, to said third control means, and to saidfirst timing means for controlling energy thereto, and

means opcratively associated with said third timing means and with saidfourth control means for locking out said first and second timing means,

said third timing means being separately connected to said opening andclosing means for intermittent operation of said well,

whereby any liquid above one of said valves in said tubing is lifted tothe earth's surface.

2. Apparatus in accordance with claim 1 in which the signal-providingmeans is electric.

3. Apparatus in accordance with claim 1 in which the signal-providingmeans is hydraulic.

4. Apparatus in accordance with claim 1 in which the signal-providingmeans is pneumatic.

,iireos 5. In a well having a pipe string therein communicating fluidlywith a subsurface earth interval in which a tubing is arranged extendingto the earths surface providing an annulus with the inner wall of thepipe string,

said tubing having arranged therein a plurality of verticallyspaced-apart mechanically operated gas lift valves operable from theearths surface, wherein means are provided for injecting a gasiformfluid into the annulus, apparatus for continuous and intermittentoperation of said well which comprises:

means at the earths surface operatively connected to said gas liftvalves and responsive to a signal which is a function of a change inpressure in said annulus after lapse of a predetermined period of timefor selectively remotely opening and closing said valves,

means operatively connected to said opening and closing means forproviding said signal,

said means for providing said signal comprising:

first and second pressure-responsive means fluidly communicating withsaid injection means,

first, second, and third timing means,

first control means operatively connected to said first timing means forcontrolling energy supplied to said signal producing means,

second control means operatively connected to said second timing means,

third control means cperatively connected to said firstpressure-responsive means, to said first and second control means, andto said second timing means for controlling energy thereto,

fourth control means operatively connected to said secondpressure-responsive means, to said third control means, and to saidfirst timing means for controlling energy thereto, and

means operatively associated with said third timing means and with saidfourth control means for locking out said first and second timing means,

said third timing means being separately connected to said opening andclosing means for intermittent operation of said well,

whereby any liquid above one of said valves in said tubing is lifted tothe earths surface.

6. Apparatus in accordance with claim 5 in which the signal-providingmeans is electric.

7. Apparatus in accordance with claim 5 in which the signal-providingmeans is hydraulic.

8. Apparatus in accordance with claim 5 in which the signal-providingmeans is pneumatic.

9. Apparatus in accordance with claim 5 wherein said opening and closingmeans includes means for raising and lowering said tubing string.

10. Apparatus in accordance with claim 9 in which the raising andlowering means comprises a rack and pinion.

11. Apparatus in accordance with claim 5 wherein said opening andclosing means includes wireline operated means engageable anddisengageable with said valves.

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1. IN A WELL HAVING A PIOPE STRING THEREIN COMMINICATING FLUIDLY WITH A SUBSURFACE EARTH INTERVAL IN WHICH A TUBING IS ARRANGED EXTENDING TO THE EARTH''S SURFACE PROVIDING AN ANNULUS WITHTHE INNER WALL OF THE PIPE STRING, SAID TUBING HAVING ARRANGED THEREIN A PLURALITY OF VERTICALLY SPACED-APART MECHANICALLY OPERATED GAS LIFT VALVES OPERABLE FROM THE EARTH''S SURFACE, WHEREIN MEANS ARE PROVIDED FOR INJECTING A GASIFORM FLUID INTO THE WELL, APPARATUS FOR CONTINUOUS AND INTERMITTANT OPERATION OF SAID WELL WHICH COMPRISES: MEANS AT THE EARTH''S SURFACE OPERATIVELY CONNECTED TO SAID GAS LIFT VALVES AND RESPONSIVE TO A SIGNAL WHICH IS A FUNCTION OF A CHANGE IN PRESSURE IN SAID WELL AFTER LAPSE OF A PREDETERMINED PERIOD OF TIME FOR SELECTIVELY REMOTELY OPENING AND CLOSING SAID VALVES, MEANS OPERATIVELY CONNECTED TO SAID OPENING AND CLOSING MEANS FOR PROVIDING SAID SIGNAL, SAID MEANS FOR PROVIDING SAID SIGNAL COMPRISING: FIRST AND SECOND PRESSURE-RESPONSIVE MEANS FLUIDLY COMMUNICATING WITHSAID INJECTION MEANS, FIRST, SECOND, AND THIRD TIMING MEANS, FIRST CONTROL MEANS OPERATIVELY CONNECTED TO SAID FRIST TIMING MEANS FOR CONTROLLING ENERGY SUPPLIED TO SAID SIGNAL PRODUCING MEANS, SECOND CONTROL MEANS OPERATIVELY CONNECTED TO SAID SECON TIMING MEANS, THIRD CONTROL MEANS OPERATIVELY CONNEECTED TO SAID FIRST PRESSURE-RESPONSIVE MEANS, TO SAID FIRST AND SECOND CONTROL MEANS, AND TO SAID SECOND TIMING MEAN SFOR CONTROLLING GENERGY THERETO, FOURTH CONTROL MEANS OPERATIVELY CONNECTED TO SAID SECOND PRESS-RESPONSIVE MEANS, TO SAID THIRD CONTROL MEANS, AND TO SAID FIRST TIMING MEANS FOR CONTROLLING ENERGY THERETO, AND MEANS OPERATIVELY ASSOCIATED WITH SAID THIRD TIMING MEANS AND WITH SAID FOURTH CONTROL MEANS FOR LOCKING OUT SAID FIRST AND SECOND TIMING MEANS, SAID THIRD TIMING MEANS BEING SEPARATELY CONNECTED TO SAID OPENING AND CLOSING MEANS FOR INTERMITTENT OPERATION OF SAID WELL, WHEREBY ANY LIQUID ABOVE ONE OF SAID VALVES IN SAID TUBING IS LIFTED TO THE EARTH''S SURFACE. 